Shah Rukh had a special reason behind this: He wanted the Big B to experience the anxiety that all contestants go through when they take the hot seat to play the game show, said a source.
Shah Rukh even asked Amitabh few questions to give him the real feel of the show, and the 69-year-old humbly answered all the queries.
Big B also gave in to Shah Rukh's request and recited his famous dialogue - "Rishte mein toh hum tumhare baap lagte hain" from the film "Shahenshah".
Shah Rukh was on the show to promote his upcoming production "RA.One" releasing Oct 26.
The episode featuring the actors will air on Sony Entertainment Television Thursday.